Association of iron deficiency with incident cardiovascular diseases and mortality in the general population

Impact of serum iron levels on in-hospital mortality and clinical outcomes in patients with ST segment elevation myocardial infarction undergoing emergency percutaneous coronary intervention: a retrospective analysis

BACKGROUND

Despite advances in percutaneous coronary intervention (PCI) for ST segment elevation myocardial infarction (STEMI), in-hospital mortality remains a concern, highlighting the need for the identification of additional risk factors such as serum iron levels.

OBJECTIVE

This study aims to assess the relationship between serum iron levels and in-hospital mortality among patients with STEMI undergoing emergency PCI.

METHODS

A total of 685 patients diagnosed with STEMI, treated with emergency PCI between January 2020 and June 2023, were included in this retrospective observational study. Participants were categorized based on serum iron levels into a low serum iron group (Fe <7.8 μmol/L) and a control group (Fe ≥7.8 μmol/L). Clinical and biochemical variables were compared between the groups. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for in-hospital mortality.

RESULTS

The low serum iron group demonstrated significantly higher in-hospital mortality rates (9.3 vs. 1.0%, P  < 0.05) compared with the control group. Multivariate logistic regression revealed that a left ventricular ejection fraction less than 40% upon admission [odds ratio (OR), 8.01; 95% confidence interval (CI), 1.230-52.173; P  = 0.029], the occurrence of no-reflow during PCI (OR, 7.13; 95% CI, 1.311-38.784; P  = 0.023), and serum iron levels below 7.8 μmol/L (OR, 11.32; 95% CI, 2.345-54.640; P  = 0.003) were independent risk factors for in-hospital mortality.

CONCLUSION

Low serum iron levels are associated with increased in-hospital mortality in patients with STEMI undergoing emergency PCI. Serum iron levels may serve as an independent prognostic marker and could inform risk stratification and therapeutic targeting in this patient population.

Both low and high body iron stores relate to metabolic syndrome in postmenopausal women: Findings from the VIKING Health Study-Shetland (VIKING I)

BACKGROUND

There are conflicting results among studies on the association between serum ferritin (SF) and metabolic syndrome (MetS), and by groups of sex/menopausal status. To date, there are no studies on British populations. The SF-MetS association might be U/J-shaped. We evaluated whether SF was independently associated with MetS (harmonized definition) in people from Shetland, Scotland.

METHODS

We analysed cross-sectional data from the Viking Health Study-Shetland (589 premenopausal women [PreMW], 625 postmenopausal women [PostW] and 832 men). Logistic regressions using two approaches, one with the lowest sex and menopausal status-specific ferritin quartile (Q) as the reference and other using the middle two quartiles combined (2-3) as the reference, were conducted to estimate the SF-MetS association. The shape of the association was verified via cubic spline analyses. The associations were adjusted for age, inflammatory and hepatic injury markers, alcohol intake, smoking and BMI.

RESULTS

Prevalence of MetS was 18.3%. Among PostMW both low and high SF were associated with MetS (fully adjusted odds ratios [95% confidence interval] compared to the middle two quartiles combined were: 1.99 [1.17-3.38] p =.011 for Q1 and 2.10 [1.27-3.49] p =.004 for Q4) This U-shaped pattern was confirmed in the cubic spline analysis in PostMW with a ferritin range of 15-200 ug/L. In men, a positive association between ferritin quartiles with Q1 as the reference, did not remain significant after adjustment for BMI.

CONCLUSION

Extreme quartiles of iron status were positively associated with MetS in PostMW, while no SF-MetS associations were found in men or PreMW. The ferritin-MetS association pattern differs between populations and U/J-shaped associations may exist.

Maternal hemoglobin and iron status in early pregnancy and childhood cardiac outcomes

BACKGROUND & AIMS

Dysregulation of iron homeostasis is associated with cardiac alterations in a sex-dependent manner in adults. It is unknown whether iron status during pregnancy has long-term impact on cardiovascular health, and if this association is influenced by sex. Therefore, this study aimed to evaluate sex-specific association between maternal iron status during early pregnancy and cardiac outcomes in children aged 10 years.

METHODS

In a population-based cohort study among 1972 mother-child pairs, hemoglobin and ferritin were measured in early pregnancy (<18 weeks) and categorized into anemia (hemoglobin<11 g/dL), elevated hemoglobin (hemoglobin≥13.2 g/dL), iron deficiency (ferritin<15 μg/L), and iron overload (ferritin>150 μg/L). At 10 years of age, cardiac MRI was performed to measure right and left cardiac outcomes of function (ventricular end-diastolic volume (RVEDV and LVEDV) and ejection fraction (RVEF and LVEF)), and structure (left ventricular mass (LVM), and left ventricular mass-to-volume ratio (LMVR)). Results are presented for boys and girls separately and models were adjusted for confounders and multiple testing.

RESULTS

In boys, one standard deviation score (SDS) increase in maternal hemoglobin was associated with lower RVEDV and LVEDV (difference (95%CI) -0.10 (-0.17, -0.03) SDS and -0.09 (-0.16, -0.03) SDS, respectively). In boys, maternal anemia, as compared to normal hemoglobin levels, was associated with higher LVEDV (difference 0.34 (0.10, 0.59) SDS). No associations were observed for other cardiac outcomes and for ferritin in boys. No associations were observed in girls.

CONCLUSION

In boys, dysregulated iron status during early pregnancy might permanently alter cardiovascular RVEDV and LVEDV function. Underlying mechanisms need further study.

Iron Deficiency and Incident Heart Failure in Older Community-Dwelling Individuals

AIMS

Among persons with prevalent heart failure (HF), iron deficiency has been linked to HF admissions, and intravenous iron replacement improves HF outcomes. Recent studies in persons with chronic kidney disease (CKD) demonstrate that iron deficiency is associated with incident HF. This study aimed to determine the relationship of iron status with incident HF in community-dwelling older adults irrespective of their kidney function.

METHODS

In this case-cohort study, 1,006 Cardiovascular Health Study participants (785 from the random sub-cohort [including 193 HF cases] and 221 additional HF cases [N = 414 total HF cases]) aged ≥ 65 years without HF (41% with CKD), we used weighted Cox models to evaluate associations of iron status with incident HF. Participants were categorized based on quartiles of transferrin saturation and ferritin as "iron replete" (27.3%), "functional iron deficiency" (7.7%), "iron deficiency" (11.8%), "mixed iron deficiency" (5.6%), "high iron" (9.3%) and "non-classified" (38.1%), consistent with prior studies.

RESULTS

Compared to older persons who were iron replete, those with iron deficiency were at higher risk of incident HF (HR 1.47; 1.02-2.11) in models adjusting for demographics, HF risk factors, and estimated glomerular filtration rate. Other iron categories did not associate with incident HF. The relationship of iron deficiency with incident HF did not differ by CKD status (interaction P value 0.2).

CONCLUSIONS

Among community-dwelling elders, iron deficiency is independently associated with incident HF, an association that was similar irrespective of CKD status. Our findings support conduct of clinical trials of iron replacement for prevention of HF in older adults with iron deficiency.

Iron Metabolic Biomarkers and the Mortality Risk in the General Population: A Nationwide Population-Based Cohort Study

Context

Iron is an essential element in the human body and plays a critical role in many physiological and cellular processes. However, the association between iron status and the risk of all-cause or cause-specific mortality has not been well-investigated. And it is unclear whether the association between iron metabolic biomarkers and the risk of mortality differs between people with and without diabetes mellitus (DM).

Objective

This work aimed to investigate associations between iron metabolic biomarkers and all-cause and cause-specific mortality risk in the general population, and heterogeneities in the associations among population with and without DM..

Methods

A total of 29 166 adults from the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999 to 2010 were included, with linkage to the National Death Index to December 31, 2019. Cox proportional-hazard models and Fine-Gray subdistribution hazard models were used to estimate associations between iron metabolic biomarkers and outcomes.

Results

During a median follow-up of 18.83 years, 9378 deaths were observed, including 3420 cardiovascular disease (CVD) deaths and 1969 cancer deaths. A significant linear association between serum ferritin (SF) and all-cause mortality was observed among the overall population and those without DM. J-shaped associations between transferrin saturation (TSAT) and all-cause and CVD mortality were observed among all populations. In the overall population, compared to the first quartile (Q1) group, the adjusted hazard ratio (HR) (95% CI) for all-cause mortality was 1.07 (1.00-1.15), 1.05 (0.98-1.12), 1.13 (1.05-1.21) in Q2, Q3, and Q4 groups for SF, while the HR was 0.94 (0.88-0.99), 0.92 (0.86-0.97), and 0.93 (0.88-0.99) for TSAT. In individuals without DM, the adjusted HR of the Q4 of SF were 1.19 (1.03-1.37) for CVD mortality and 1.25 (1.05-1.48) for cancer mortality. In individuals with DM, the adjusted HRs of the Q4 of TSAT were 0.76 (0.62-0.93) for CVD mortality and 1.47 (1.07-2.03) for cancer mortality.

Conclusion

Iron metabolism abnormalities increase mortality risk in the general population. The associations of iron status with mortality were significantly different between individuals with and without DM, which indicated tailored strategies for iron homeostasis are needed.

Iron deficiency: prevalence, mortality risk, and dietary relationships in general and heart failure populations

Background

Iron deficiency (ID) is the most common nutritional deficiency, with little research on its prevalence and long-term outcomes in the general population and those with heart failure (HF). Both the relationships between dietary iron and ID, as well as dietary folate and ID, are understudied.

Methods

We used data from the National Health and Nutrition Examination Survey from 1999 to 2002 to investigate the prevalence, prognosis, and relationship between dietary and ID defined by different criteria in the general population (n = 6,660) and those with HF (n = 182).

Results

There was no significant difference in the prevalence of ID between HF patients and the general population after propensity score matching. Transferrin saturation (TSAT) <20% was associated with higher 5-year all-cause mortality (HR: 3.49, CI: 1.40-8.72, P = 0.007), while ferritin <30 ng/ml was associated with higher 10-year (HR: 2.70, CI: 1.10-6.67, P = 0.031) and 15-year all-cause mortality (HR: 2.64, CI: 1.40-5.00, P = 0.003) in HF patients. Higher dietary total folate but dietary iron reduced the risk of ID (defined as ferritin <100 ng/ml) in HF patients (OR: 0.80; 95% CI: 0.65-1.00; P = 0.047).

Conclusions

The prevalence of ID was identical in HF and non-HF individuals. Ferritin <30 ng/ml was associated with long-term outcomes whereas TSAT <20% was associated with short-term prognosis in both the general population and HF patients. A diet rich in folate might have the potential for prevention and treatment of ID in HF patients.

Consumption of foods contaminated with heavy metals and their association with cardiovascular disease (CVD) using GAM software (cohort study)

Introduction

Heavy metals can enter the environment and food through industrial activities, acid rain, chemical fertilizers, pesticides, and sewage. A large amount of these metals is dangerous because they tend to bio accumulate. A concern with these metals is the long-term, low-dose exposure seen in the general population. HMs can cause disorders in the cardiovascular system through various mechanisms such as the production of free radicals, DNA damage, lipid peroxidation, and oxidative stress.

Material and method

Food items measured in the present study included rice, bread, and vegetables. 210 participants (105 controls and 105 patients) were randomly selected for this study. The demographic information of the subjects was obtained from the Hoveyzeh Cohort Center. The relationship between heavy metals in food and cardiovascular diseases is investigated by The Generalized Additive Model (GAM).

Result

The results of the present study showed that when urine Cd was smoothed based on rice Cd, there was a significant correlation between urine Cd and Cd consumed in vegetables and rice. The GAM coefficient for urinary Cd excreted in case-control groups and Cd consumed in vegetables were 479.79(SE: 6.49-73.87) and 818.56(SE: 11.96-68.43), respectively, and for rice consumed, it was 0.03(SE: 0.015-2.103) and 0.04(SE: 0.017-2.338), respectively. The GAM coefficient for As consumption in vegetables and As in urine of case and control groups was 1.61 (SE: 9.48-0.16) and 22.36 (SE: 13.60-1.64), respectively. The same coefficient for rice consumption in case and control groups was 4.5 (SE: 0.62-7.22) and 10.48 (SE: 1.46-7.16), respectively. There was a very strong and significant correlation between the Sr in the urine of both groups and the Sr in the food consumed, so that the urinary Sr in the control group is excreted more than in the cardiovascular group.

Conclusion

GAM analysis indicates that As in vegetable and rice is more than the standard limitation value. Also, Sr and Cd in vegetables, rice, and bread were more than the standard limitation value. According to the GAM model As had a significant value in rice and vegetables indicating that As is more than the standard limitation value, therefore, it is associated with CVD.

Inflammation as a New Therapeutic Target among Older Patients with Ischemic Heart Disease

Cardiovascular (CV) diseases remain a global health challenge, with ischemic heart disease (IHD) being the primary cause of both morbidity and mortality. Despite optimal pharmacological therapy, older patients with IHD exhibit an increased susceptibility to recurrent ischemic events, significantly impacting their prognosis. Inflammation is intricately linked with the aging process and plays a pivotal role in the evolution of atherosclerosis. Emerging anti-inflammatory therapies have shown promise in reducing ischemic events among high-risk populations. This review aims to explore the potential of targeted anti-inflammatory interventions in improving clinical outcomes and the quality of life for older patients with IHD.

Maternal hemoglobin and iron status in early pregnancy and risk of respiratory tract infections in childhood: A population-based prospective cohort study

BACKGROUND

Maternal hemoglobin and iron status measures during pregnancy might affect the developing fetal respiratory system leading to adverse respiratory conditions. Our aim was to assess the associations of maternal hemoglobin and iron status measures during pregnancy with the risk of respiratory tract infections in children until 10 years of age.

METHODS

In a population-based cohort study among 5134 mother-child pairs, maternal hemoglobin and iron status including ferritin, transferrin, and transferrin saturation were measured during early pregnancy. In children, physician-attended respiratory tract infections from age 6 months until 10 years were assessed by questionnaires. Confounder-adjusted generalized estimating equation modeling was applied.

RESULTS

After taking multiple testing into account, high maternal ferritin concentrations and low maternal transferrin saturation during pregnancy were associated with an overall increased risk of upper, not lower, respiratory tract infections until age 10 years of the child [OR (95% CI: 1.23 (1.10, 1.38) and 1.28 (1.12, 1.47), respectively)]. High maternal transferrin saturation during pregnancy was associated with a decreased and increased risk of upper respiratory tract infections at 1 and 6 years, respectively, [OR (95% CI: 0.60 (0.44, 0.83) and 1.54 (1.17, 2.02))]. Observed associations were suggested to be U-shaped (p-values for non-linearity ≤.001). Maternal hemoglobin and iron status measures during pregnancy were not consistently associated with child's gastroenteritis and urinary tract infections, as proxies for general infection effects.

CONCLUSION

High maternal ferritin and low transferrin saturation concentrations during early pregnancy were most consistently associated with an overall increased risk of child's upper, not lower, respiratory tract infections.

Iron Deficiency Might Impair the Recovery of Left Ventricular Function after Surgical Revascularization in Diabetic Patients: A Retrospective Study

Background

Iron deficiency (ID) is one of the most common micronutrient deficiencies affecting public health. Studies show that ID affects the prognosis of patients with heart disease, including heart failure, coronary artery disease and myocardial infarction. However, there is limited information regarding the impact of ID on patients undergoing cardiac surgery. This study aimed to evaluate the influence of preoperative ID on the prognosis of type 2 diabetes mellitus (T2DM) patients undergoing coronary artery bypass grafting (CABG).

Methods

In the Glycemic control using mobile-based intervention in patients with diabetes undergoing coronary artery bypass to promote self-management (GUIDEME) study, patients with T2DM undergoing CABG were prospectively recruited. In this study, only those patients with preoperative iron metabolism results were enrolled. Patients were grouped based on the presence of preoperative ID. The primary endpoint was defined as the significant improvement of follow-up ejection fraction (EF) compared to postoperative levels (classified according to the 75th percentile of the change, and defined as an improvement of greater than or equal to 5%). Univariable logistic regression was performed to explore the potential confounders, followed by multiple adjustment.

Results

A total of 302 patients were enrolled. No deaths were observed during the study period. A higher incidence of the primary endpoint was observed in the ID group (25.4% vs 12.9%, p = 0.015). The postoperative and follow-up EF were similar beween the two groups. In the regression analysis, ID was noticed to be a strong predictor against the significant improvement of EF in both univariable (odds ratio [OR]: 0.44, 95% confidence interval [CI]: 0.22-0.86, p = 0.017) and multivariable (OR: 0.43, 95% CI: 0.24-0.98, p = 0.043) logistic regression. In the subgroup analysis, ID was a predictor of significant improvement of EF in age ≤ 60 years, male, EF ≤ 60%, and on-pump CABG patients.

Conclusions

In T2DM patients undergoing CABG, ID might negatively affect the early recovery of left ventricular systolic function in terms of recovery of EF 3-6 months after surgery, especially in patients age ≤ 60 years, males, EF ≤ 60% and in those undergoing on-pump CABG.

Mendelian randomization study reveals a causal relationship between serum iron status and coronary heart disease and related cardiovascular diseases

Background

Growing observational studies have shown that abnormal systemic iron status is associated with Coronary heart disease (CHD). However, these results from observational studies was not entirely consistent.It remains unclear whether this relationship represents causality.It is necessary to explore the causal relationship between iron status and CHD and related cardiovascular diseases (CVD).

Objective

We aimed to investigate the potential casual relationship between serum iron status and CHD and related CVD using a two-sample Mendelian randomization (MR) approach.

Methods

Genetic statistics for single nucleotide polymorphisms (SNPs) between four iron status parameters were identified in a large-scale genome-wide association study (GWAS) conducted by the Iron Status Genetics organization. Three independent single nucleotide polymorphisms (SNPs) (rs1800562, rs1799945, and rs855791) aligned with four iron status biomarkers were used as instrumental variables. CHD and related CVD genetic statistics We used publicly available summary-level GWAS data. Five different MR methods random effects inverse variance weighting (IVW), MR Egger, weighted median, weighted mode, and Wald ratio were used to explore the causal relationship between serum iron status and CHD and related CVD.

Results

In the MR analysis, we found that the causal effect of serum iron (OR = 0.995, 95% CI = 0.992-0.998, p = 0.002) was negatively associated with the odds of coronary atherosclerosis (AS). Transferrin saturation (TS) (OR = 0.885, 95% CI = 0.797-0.982, p = 0.02) was negatively associated with the odds of Myocardial infarction (MI).

Conclusion

This MR analysis provides evidence for a causal relationship between whole-body iron status and CHD development. Our study suggests that a high iron status may be associated with a reduced risk of developing CHD.

Perioperative Tracking of Intravenous Iron in Patients Undergoing On-Pump Cardiac Surgery: A Prospective, Single-Center Pilot Trial

BACKGROUND

Preoperative intravenous iron administration is a frequently used patient blood management procedure. If the timeframe of intravenous iron administration before surgery is short, (1) the concentration of the intravenous iron compound might still be high in patients' plasma when undergoing surgery and (2) this iron in patients' plasma is at risk to be lost due to blood loss. The aim of the current study was, therefore, to track the iron compound ferric carboxymaltose (FCM) before, during, and after cardiac surgery requiring cardiopulmonary bypass, with an emphasis on intraoperative iron losses in shed blood and potential recovery through autologous cell salvage.

METHODS

Concentrations of FCM were analyzed in patients' blood using a hyphenation of liquid chromatography and inductively coupled plasma-mass spectrometry to distinguish between pharmaceutical compound FCM and serum iron. In this prospective, single-center pilot trial, 13 anemic and 10 control patients were included. Anemic patients with hemoglobin levels ≤12/13 g/dL in women and men were treated with 500 milligrams (mg) intravenous FCM 12 to 96 hours before elective on-pump cardiac surgery. Patients' blood samples were collected before surgery and at days 0, 1, 3, and 7 after surgery. One sample each was taken of the cardiopulmonary bypass, the autologous red blood cell concentrate generated by cell salvage, and the cell salvage disposal bag.

RESULTS

Patients who had received FCM <48 hours before surgery had higher FCM serum levels (median [Q1-Q3], 52.9 [13.0-91.6]) compared to ≥48 hours (2.1 [0.7-5.1] µg/mL, P = .008). Of 500-mg FCM administered <48 hours, 327.37 (257.96-402.48) mg were incorporated compared to administration ≥48 hours with 493.60 (487.78-496.70) mg. After surgery, patients' plasma FCM concentration in the FCM <48 hours group was decreased (-27.1 [-30 to -5.9] µg/mL). Little FCM was found in the cell salvage disposal bag (<48 hours, 4.2 [3.0-25.8] µg/mL, equivalent to 29.0 [19.0-40.7] mg total; equivalent to 5.8% or 1/17th of the 500 mg FCM initially administered), almost none in the autologous red blood cell concentrate (<48 hours, 0.1 [0.0-0.43] µg/mL).

CONCLUSIONS

The data generate the hypotheses that nearly all FCM is incorporated into iron stores with administration ≥48 hours before surgery. When FCM is given <48 hours of surgery, the majority is incorporated into iron stores by the time of surgery, although a small amount may be lost during surgical bleeding with limited recovery by cell salvage.

Iron deficiency and cardiovascular disease

Iron deficiency (ID) is common in patients with cardiovascular disease. Up to 60% of patients with coronary artery disease, and an even higher proportion of those with heart failure (HF) or pulmonary hypertension have ID; the evidence for cerebrovascular disease, aortic stenosis and atrial fibrillation is less robust. The prevalence of ID increases with the severity of cardiac and renal dysfunction and is probably more common amongst women. Insufficient dietary iron, reduced iron absorption due to increases in hepcidin secondary to the low-grade inflammation associated with atherosclerosis and congestion or reduced gastric acidity, and increased blood loss due to anti-thrombotic therapy or gastro-intestinal or renal disease may all cause ID. For older people in the general population and patients with HF with reduced ejection fraction (HFrEF), both anaemia and ID are associated with a poor prognosis; each may confer independent risk. There is growing evidence that ID is an important therapeutic target for patients with HFrEF, even if they do not have anaemia. Whether this is also true for other HF phenotypes or patients with cardiovascular disease in general is currently unknown. Randomized trials showed that intravenous ferric carboxymaltose improved symptoms, health-related quality of life and exercise capacity and reduced hospitalizations for worsening HF in patients with HFrEF and mildly reduced ejection fraction (<50%). Since ID is easy to treat and is effective for patients with HFrEF, such patients should be investigated for possible ID. This recommendation may extend to other populations in the light of evidence from future trials.

Celiac Disease Patients With Coronary Artery Disease: A Nationwide Population-Based Study

Background

Coronary artery disease (CAD) is associated with celiac disease (CD) with limited evidence. However, the common risk factors linking CD and CAD are still lacking in the literature. Known CAD risk factors include hypertension, hyperlipidemia, type 2 diabetes, obesity, and tobacco use. Common risk factors linking CD and CAD are poorly documented.

Objective

There are three objectives: Firstly, to evaluate potential demographic differences between CD patients with CAD and without CAD. Secondly, to analyze the risk factors of CAD in CD patients. Lastly, to compare CD-CAD and matched non-CD CAD to determine whether there are additional CAD risks in individuals with CD.

Methods

The study is a nationwide retrospective case-control study. The National Inpatient Sample (NIS) database was used to identify patients admitted between 2016 and 2018 with a principal or secondary diagnosis of CD. We analyzed sociodemographic and clinical risk factors of CAD in CD patients and compared the CD-CAD population with the matched non-CD CAD cohort.

Results

Out of 23,441 hospitalizations with CD in 2016-2018, 4244 (18%) were found to have CAD. Established CAD risk factors identified in CD patients included hypertension, hyperlipidemia, type 2 diabetes, and a family history of CAD. In contrast, tobacco use is not a CAD risk factor in CD patients. Female patients with CD had 55% lesser odds of CAD than male patients. The odds of CAD in CD patients with hyperlipidemia were five times higher, 1.2 times higher with essential hypertension, and two times higher with type 2 diabetes. Patients with CAD had a higher prevalence of iron deficiency anemia (9.33% CD-CAD and 8.28% non-CAD CD Vs. 7.32% non-CD CAD).

Conclusions

Our study confirms that, as with non-CD individuals, males and the White race are at increased CAD risk in the CD population. CD-CAD patients have a higher hyperlipidemia prevalence than non-CD CAD patients. CD patients with type 1 diabetes have an early diagnosis of CAD compared to CD patients with type 2 diabetes. Iron deficiency anemia is a statistically significant risk factor for CAD in CD patients.